I have been producing cad fire plans with fire risk assessments using auto cad and most recipients really appreciate the pictorial view of the fire precautions. Also fire evacuation plans can be simply draw showing the internal exit routes exit doors and assembly points.
If the original drawings can be obtained from architects then the fire plan production is quite simple and most architects are quite happy to do this as under the building regs there is a requirement to provide information for the FRA.
I produced my own symbols in cad and saved them as a plan key so that they could be used in other drawings. If you have to draw from scratch then making a single line drawing is simple if you are not requiring scale drawings, Plans in PDF or scanned can be brought into the cad program and then just trace over the document, on completion the PDF can be removed and you are left with the traced drawing.
There are some free cad programs available check link below. look for a compatibility with .dwg or .dxf format as these are the industry standard and therefore can be shared.
http://cad.about.com/od/Personal_CAD/tp/Five-Top-Free-Cad-Packages.htmIf you need any more advice or an example of what I have done.